The present invention relates in general to the handling of palletized laden containers in a manner to transfer tiers of the containers from their pallets in the form of a neatly cubed stack. More particularly, the invention relates to the automatic handling of successive pallets loaded with tiers of filled produce boxes in a manner to automatically extricate the pallet from the stack of boxes and to tightly cube a desired number of tiers of the boxes in order to maximize efficient use of the so called cube space of the cargo vehicle into which tiers of the boxes are loaded.
Boxes which have been filled with produce, e.g., heads of lettuce, and sealed are hand loaded on 40".times.90" pallets, six tiers high in the field. Clamp type lift trucks pick up one or more tiers of boxes on one pallet and transfer them to another pallet in a process of restacking to final pre-determined load heights of up to eight tiers. In this process clamping pressure is applied to the box side walls of two rows of boxes, one or more tiers high, with sufficient force to resist their falling during the restacking operation. The clamping operation damages both product and container.
Each pallet load, when received from the field, has a slip sheet of corrugated board placed between the boxes and pallet. After the restacking operation, large platform fork lift trucks with hydraulic operated buck boards and slip sheet grips are used to grab the slip sheet and transfer the load from pallet to platform. If the slip sheet tears (a common occurence) another fork lift must be used in the operation to push the stubborn load off the pallet and onto the fork platform. This "two fork lift" alternate method of transfer adds to product and container damage plus undesirable abuse to pallets.
Hand loading, trucking to the cooler, and fork lift handling before and after cooling contributes to a very loose pallet load with boxes protruding beyond the 90" pallet 4" to 6". By use of fork lifts the load is forced through large "funnel plates" hinged against the inside walls of the van. The protruding boxes are physically forced into conformity with the van side walls. As a result, several of the individual boxes will undergo stresses often resulting in container failure and consequent injury to the product enclosed therein Further, the entire prior art process requires utilization of several lift trucks in order to keep a constant flow of loaded pallets in movement from the packing house dock into the interior of the van.